Sidewall plunging tire air pressure gauge

ABSTRACT

A tire air pressure gauge that measures air pressure without connecting to the inside of the tire is disclosed. It generally consists of four parts: a handle, a plunger, a spring, and an indicator bar. The plunger is retractably mounted in the handle through the spring. The indicator bar is also slidably mounted on the handle. When plunged against the side wall of a tire, the plunger will retract, and will push the indicator bar outward. The amount of the portion of the indicator bar that is pushed out, indicates how high the air pressure inside the tire is. The more the indicator bar is pushed out, the higher the air pressure inside the tire.

BACKGROUND--FIELD OF INVENTION

The present invention is related to tire air pressure gauges formeasuring air pressure of pneumatic tires.

BACKGROUND--PRIOR ART

Heretofore tire air pressure gauges measure tire air pressure by tappinginto the inside of the tires so that the high pressure area inside thetire is pneumatically connected to the measuring gauge. To obtainaccurate measurements under this arrangement, the gauge must be tightlypressed against the tire stem in an exactly lined up position,otherwise, leakage of air will occur, the resulting reading of pressurewill not be accurate, and after a few tries, due to the leakage of air,the pressure inside the tire will likely be a lot lower than theoriginal pressure.

To a lot of people, measuring tire pressure is a very bothersome anddifficult, if not impossible, task. A lot of tires are left uncheckedfor weeks and months due to the apprehension of the chore. As a result,tires are damaged, vehicular performances suffer, and accidents occur.

OBJECTS AND ADVANTAGES

The object of the present invention is to provide a tire air pressuregauge that is extremely easy to use, so that measuring tire pressure isextremely simple and quick.

Another object of the invention is to provide a tire air pressure gaugethat does not tap into the inside of the tire, thus air leakage willnever occur due to the performing of air pressure measurement.

Still another object of the invention is to provide a tire air pressuregauge that does not require much skill to operate. All that needs to bedone is to point and punch.

SUMMARY OF THE INVENTION

The tire air pressure gauge of the invention does not pneumaticallyconnect to the inside of the tire. It measures the pressure by measuringthe degree of retraction of a plunger when plunged onto the side wall ofa tire under certain conditions.

The gauge basically consists of 4 parts: a handle, a plunger, a spring,and an indicator. The plunger is slidably mounted on the handle throughthe spring. The indicator is also slidably mounted on the handle tomeasure the distance of retraction of the plunger.

When pressed against the side wall of a tire, the handle through thespring, forces the plunger to plunge the tire wall. The plunger willcause the side wall to deflect. And at the same time the plunger willretract into the handle against the force of the spring. The distance ofretraction of the plunger is related to the depth of deflection of theside wall of the tire. The depth of deflection of the tire wall is alsorelated to the air pressure inside the tire. Hence the air pressure ofthe tire is related to the distance of retraction of the plunger. Thehigher the pressure, the more retraction of the plunger, and vice versa.By measuring the distance of retraction of the plunger, the indicatorgives the reading of the air pressure inside the tire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal section of the first preferred embodiment,showing the embodiment in a condition when it is not being used.

FIG. 2 is a longitudinal section of the first preferred embodiment,showing the embodiment in a condition when it is being used to check theair pressure of a tire.

FIG. 3 is a longitudinal section of the second preferred embodiment,showing the embodiment in a condition when it is not being used.

FIG. 4 is a cross section taken from line 4--4 of FIG. 3.

FIG. 5 is a cross section taken from line 5--5 of FIG. 3.

FIG. 6 is a cross section taken from line 6--6 of FIG. 3.

FIG. 7 is a longitudinal section of the second preferred embodiment,showing the embodiment in a condition when it is being used to check theair pressure of a tire.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 and FIG. 2 are longitudinal sections of a preferred embodiment ofthe invention, wherein FIG. 1 shows the embodiment in a condition whenit is not being used, and FIG. 2 shows the embodiment in a conditionwhen it is pressed all the way against the side wall of a tire tomeasure the air pressure inside the tire. In FIG. 1 and FIG. 2, 11 is ahandle body, 12 is a plunger body, 13 is a plunger piston, 14 is aspring, 15 is a indicator bar, 16 is a rear bearing, 17 is a frontbearing, 18 is a stopper, and 19 is the side wall of a tire.

Handle body 11 is a cylindrical housing that houses plunger piston 13,part of plunger body 12, spring 14, indicator bar 15, and rear bearing16.

Plunger piston 13 fits snugly into handle body 11 so that it slidessmoothly together with plunger body 12 longitudinally. Plunger piston 13is fixedly connected to plunger body 12. Spring 14 is placedlongitudinally between the rear end of handle body 11 around rearbearing 16, and the inner area of plunger piston 13. Spring 14constantly pushes plunger piston 13 and plunger body 12 outward, so thatplunger body protrudes outward from said handle body, and will retractinward if subjected to an inward pressure that is greater than theoutward pressure of spring 14. Front bearing 17 slidably supportsplunger body 12 so that plunger body 12 slides through smoothly. Frontbearing 17 also serves as a front cap of handle body 11, to confineplunger piston 13 to the housing of handle body 11. Front bearing 17extends outward and forward to form a horn-shaped stopper 18. Whenstopper 18 hits side wall 19 of a tire, handle body 11 can not moveforward anymore, as shown in FIG. 2. This sets a predefined conditionfor measuring tire pressure, because every time the device is used,handle body 11 is pushed forward to travel a fixed distance beforestopper 18 hits the side wall of the tire. The horn-shaped stopper 18also serves as a spacer between the side wall 19 of the tire and theoperator's hand (not shown) which holds the device by its handle body11, for comfortable operation. Stopper 18, together with front bearing17, is screwed onto handle body 11.

Rear bearing 16 is screwed into the rear end of handle body 11, forslidably supporting indicator bar 15, so that indicator bar 15 can slidesmoothly longitudinally. Rear bearing 16 also provides certain frictionto indicator bar 15, so that indicator bar 15 will not slide until it ispushed. This way indicator bar 15 will hold its position that indicatesthe air pressure of the tire, until it is read and pushed to reset.

When the embodiment is pushed forward against the side wall 19 of a tireas shown in FIG. 2, the side wall 19 of the tire will deflect, andplunger 12 will retract against the pressure of spring 14. As plunger 12retracts, plunger piston 13 pushes indicator bar 15 outward untilstopper 18 hits side wall 19 of the tire. The amount of the portion ofindicator bar 15 that is pushed out, indicates the amount of retractionof plunger body 12, or the air pressure of the tire. The bigger portionthat is pushed out, the higher the air pressure. There are graduatedmarkings (not shown) on the side of indicator bar 15 to give readings ofthe air pressure.

FIG. 3, FIG. 4. FIG. 5, FIG. 6, and FIG. 7 show another preferredembodiment of the invention, wherein FIG. 3 is a longitudinal sectionthat shows the embodiment in a condition when it is not being used, FIG.4 is a cross section taken from line 4--4 of FIG. 3, FIG. 5 is a crosssection taken from line 5--5 of FIG. 3, FIG. 6 is a cross section takenfrom line 6--6 of FIG. 3, and FIG. 7 is a longitudinal section thatshows the embodiment in a condition when it is pressed all the wayagainst the side wall of a tire to measure the air pressure inside thetire.

In FIG. 3 through FIG. 7, 21 is a cylindrical plunger holder, 22 is aplunger body, 23 is a plunger piston, 24 is a spring, 25 is a markerring, 26 is a pusher rod, 27 is a stopper, 28 is a handle, 29 is alongitudinal slit on cylindrical plunger holder 21 for pusher rod 26 togo through, 30 is the side wall of a tire.

Plunger piston 23 is snugly fitted into cylindrical plunger holder 21 sothat together with plunger body 22, it slides smoothly along cylindricalplunger holder 21 longitudinally. Plunger piston 23 is fixedly connectedto plunger body 22. Spring 24 is mounted inside plunger holder 21 inbetween plunger piston 23, and the rear end of plunger holder 21. Spring24 constantly pushes plunger piston 23 and plunger body 22 outward tothe front, so that plunger body 22 protrudes outward from plunger holder21, and will retract inward when subjected to an inward pressure that isgreater than the outward pressure of spring 24. Stopper 27 is screwedonto the front end of plunger holder 21, to stop the forward movement ofplunger holder 21 when stopper 27 hits side wall 30 of the tire, asindicated in FIG. 7. Stopper 27 also serves as a bearing for slidablysupporting plunger body 22, so that plunger body 22 is held in place,and can slide in and out of plunger holder smoothly. Stopper 27 furtherserves as a cap for confining plunger piston 23 to the housing ofplunger holder 21. Handle 28 is mounted on the rear end of plungerholder 21. Handle 28 also serves as a cap to confine spring 24 to thehousing of plunger holder 21.

Pusher rod 26 is fixedly mounted on plunger piston 23, and is fittedinto longitudinal slit 29 on plunger holder 21. When plunger piston 23slides longitudinally within plunger holder 21, pusher rod 26 slidesalong longitudinal slit 29. Marker ring 25 is a ring-shaped markerslidably mounted on the outer surface of plunger holder 21 betweenpusher rod 26 and handle 28. There is certain friction between plungerholder 21 and marker ring 25, so that marker ring 25 does not slideuntil pushed.

When, by the handle 28, a user pushes the embodiment against the sidewall 30 of a tire, side wall 30 will deflect, and plunger body 22 willretract into plunger holder 21 against the pressure of spring 24, asshown in FIG. 7. This process keeps on going until stopper 27 hits sidewall 30 of the tire. At the same time, pusher rod 26 will push markerring 25 toward handle 28. The distance traveled by marker ring 25indicates the amount of retraction of plunger body 22, or the airpressure inside the tire. The farther the maker ring 25 travels, thehigher the pressure. There are graduated markings (not shown) on theouter surface of plunger holder 21 to indicate how far marker ring 25has traveled, or how far plunger body 22 has traveled, and hence howhigh the air pressure inside the tire is.

Hence the reader can see this is a novel device for checking tire airpressure quickly and easily without tapping into the inside of the tire.

While my above description contains many specificities, these should notbe construed as limitations on the scope of the invention, but rather asan exemplification of a few preferred embodiments thereof. Many othervariations are possible. Accordingly, the scope of the invention shouldbe determined not by the embodiments illustrated, but by the appendedclaims and their legal equivalents.

What is claimed is:
 1. A sidewall plunging tire air pressure gaugecomprising:a) a handle means; b) a plunger means protrudingly andretractably mounted on said handle means; c) a spring means mounted onsaid handle means for pushing said plunger means outward; d) anindicator means mounted on said handle means for indicating the amountof retraction of said plunger means; e) a stopper means mounted on saidhandle means for stopping the movement of said handle means when saidstopper means hits the sidewall of a tire.
 2. A sidewall plunging tireair pressure gauge comprising:a) a plunger holder means; b) a handlemeans mounted on said plunger holder means; c) a plunger meansprotrudingly and retractably mounted on said plunger holder means; d) aspring means mounted inside said plunger holder means, for pushing saidplunger means outward; e) an indicator means mounted on said plungerholder means, for indicating the amount of retraction of said plungermeans; f) a stopper means mounted on said plunger holder means, forstopping the movement of said plunger holder means when said stoppermeans hits the side wall of a tire.